Recombinant adeno-associated virus serotype 2-mediated RNA interference inhibits rabies virus replication

Rabies virus (RABV) is a neurotropic virus that infects the central nervous systems of humans and animals, causing fatal neurological symptoms and ultimately death. Vaccination is the only effective strategy for preventing rabies. However, once clinical symptoms appear, there is no effective treatment. Therefore, exploring effective therapeutic approaches, particularly for postexposure prophylaxis, is imperative. This study investigated the inhibitory effect of siRNA delivered by recombinant adeno-associated virus serotype 2 (rAAV2) against RABV. Specific siRNAs targeting the mRNA of the G and L genes of the RABV were designed. rAAV-G997 and rAAV-L5055 were constructed with siRNA expression cassettes. Pretreatment of neuroblastoma (NA) cells with either rAAV-G997 or rAAV-L5055 before RABV infection resulted in a considerable reduction in both the viral titer and the mRNA levels of the G and L genes. Similarly, pretreatment of baby hamster kidney (BHK-21) cells with rAAV-G997 or rAAV-L5055 prior to RABV infection decreased the expression of viral structural proteins. In a mouse model, compared with the negative control (rAAV-NC), the intracranial administration of rAAV-G997 or rAAV-L5055 conferred significant protection. When administered before challenge with the RABV CVS-11 strain, both rAAV-G997 and rAAV-L5055 significantly reduced the viral load in brain tissue, and achieved a survival rate of 90%. Similarly, in a postexposure treatment setting, both the rAAV-G997 and rAAV-L5055 groups achieved a survival rate of 88.9%. These findings demonstrate that rAAV-mediated delivery of siRNAs targeting the RABV G and L genes can inhibit viral replication in vitro and provide significant protection in vivo, highlighting the potential of rAAV2 as a therapeutic platform for treating rabies.