Mesoporous silica nanoparticle-mediated delivery of a synergistic 5-miRNA combination inhibits HSV-2 infection

Herpes simplex virus type 2 (HSV-2) is a widespread sexually transmitted pathogen responsible for genital herpes and associated with serious complications, including neonatal infections and increased HIV susceptibility. Although antiviral agents such as acyclovir are available, the emergence of drug resistance and viral latency necessitate the development of novel therapeutic approaches. RNA interference has emerged as a promising strategy against HSV-2. In our previous work, we identified a combination of five host-targeting microRNAs - miR-374a, miR-181a, miR-195, miR-29b, and miR-211, that significantly inhibited HSV-2 replication through modulation of the PI3K/AKT (phosphoinositide 3-kinase/protein kinase B) signaling pathway. In the current study, we developed a mesoporous silica nanoparticle (MSN)-based delivery system to enhance the stability of this miR-Combo. The MSN formulation was characterized for particle size, polydispersity index, zeta potential and surface morphology of developed particles by transmission electron microscopy analysis. In vitro studies in THP-1 macrophages confirmed the formulation's biocompatibility and potent antiviral activity. Moreover, in a murine model of genital HSV-2 infection, intravaginal administration of the miRNA-loaded nanoparticles (N-miR-Combo) significantly reduced viral gene expression at both transcriptional and translational levels. Furthermore, N-miR-Combo significantly suppressed HSV-2-induced pro-inflammatory mediators, while concurrently upregulating the anti-inflammatory cytokine, demonstrating dual antiviral and immunomodulatory activity relevant to HSV-2-associated immunopathology. These findings highlight the promise of MSN-mediated combinatorial miRNA delivery as an innovative and promising preclinical candidate for further therapeutic development against HSV-2 infection and antiviral resistance.