Sustained Suppression of Fusion Gene-mediated Human Respiratory Syncytial Virus Load by shRNA-based Therapeutics

Background: Human respiratory syncytial virus (HRSV) is a common cause of severe lower respiratory tract infections in infants and young children. There is no vaccine or effective treatment for this viral infection. However, Short hairpin RNA (shRNA) has many therapeutic applications, such as an effective treatment for viral infections. To find novel strategies to combat HRSV replication, specific shRNA targeting the HRSV fusion (F) gene was generated in the present study. The results were compared to ribavirin, the only Food and Drug Administration-approved antiviral drug to treat HRSV infection. Methods: ShRNA targeting a highly conserved region of the HRSV-F gene was designed to inhibit HRSV replication in vitro within the Hep-2 cell line. Real-time polymerase chain reaction (PCR) was performed to quantify virus replication and assess viral load reduction on harvested supernatant from Hep-2 cells infected with HRSV and treated with a scramble control vector, an shRNA vector, ribavirin, and a combination of ribavirin and shRNA of different concentrations at 24, 48, and 72 h after treatment. Results: Using real-time reverse transcription PCR (RT-PCR), a similar significant reduction in the viral load (99.8%) was observed by the effect of shRNA or ribavirin compared to the control group (P = 0.008). Combination treatment of ribavirin and F-shRNA resulted in a significant reduction in viral load compared to treatment with ribavirin or F-shRNA separately (P = 0.043). Conclusions: Our study demonstrated that shRNA against the F gene could potentially be used as a novel therapeutic agent for HRSV infection.