METHODS: Six unique siRNAs with three each targeting different regions of IE2 (ie2a, ie2b and ie2c) and DNA polymerase (dpa, dpb and dpc) were prepared and tested for antiviral activities. The efficacy as an antiviral was determined in in-vitro by measuring TCID50 virus titer, severity of virus-induced cytopathic effect (CPE), intracellular viral genome loads by droplet digital PCR, the degree of apoptosis in siRNA-treated cells and relative expression of viral mRNA in infected Rat Embryo Fibroblast (REF) cells.
FINDINGS: Remarkably, the siRNAs: dpa, dpb and IE2b, significantly reduced virus yield (approximately >90%) compared to control group at day 18 post infection (p.i). Changes in CPE indicated that DNA polymerase siRNAs were capable of protecting cells against CMV infection at day 14 p.i with higher efficiency than GCV (at the concentration of 300 pmol). Gene expression analysis revealed a marked down regulation of the targeted DNA polymerase gene (73.9%, 96.0% and 90.7% for dpa, dpb and dpc siRNA, respectively) and IE2 gene (50.8%, 49.9% and 15.8% for ie2a, ie2b and ie2c siRNA, respectively) when measured by RT-qPCR. Intracellular viral DNA loads showed a significant reduction for all the DNA polymerase siRNAs (dpa: 96%, dpb: 98% and dpc:92) compared to control group (P
METHODS: Cytomegalovirus replication, latency, and immune response are mediated by the intermediate early protein 2, the main protein that determines the effectiveness of drugs in cytomegalovirus inhibition. This review explains how intermediate early protein 2 can modify the action of cyclosporin A, an immunosuppressive, and antiviral drug. It also links all the pathways mediated by cyclosporin A, cytomegalovirus replication, and its encoded proteins.
RESULTS: Intermediate early protein 2 can influence the cellular cyclophilin A pathway, affecting cyclosporin A as a mediator of viral replication or anti-cytomegalovirus drug.
CONCLUSION: Cyclosporin A has a dual function in cytomegalovirus pathogenesis. It has the immunosuppressive effect that establishes virus replication through the inhibition of T-cell function. It also has an anti-cytomegalovirus effect mediated by intermediate early protein 2. Both of these functions involve cyclophilin A pathway.