Short interfering RNAs (siRNAs), short strands of genetic material, have great potential as therapeutics, but they are not always easy to deliver. Now researchers at Yale University have created nanoparticles that can deliver siRNAs that are designed to treat genital herpes resulting from HSV-2 infection, by blocking a protein on the cell surface.
The tiny PLGA (polylactic-co-glycolic acid) particles, loaded with the siRNAs, were dosed into the vaginas of mice after they were exposed to lethal levels of infection with HSV-2. Three doses of the siRNA nanoparticles improved the survival of the mice from only 9 days in untreated mice to more than 28 days in treated mice. According to the researchers, this is the longest survival seen in this mouse model after treatment with siRNA.
The treatment works by blocking the protein nectin-1 on the surface of the cell. This stops cell-to-cell transmission of the virus, cutting the spread of the infection.
"This work provides proof-of-concept that these siRNA delivery vehicles are promising options for topical, localized therapeutics for sexually transmitted infections," Yale postdoctoral researcher Jill Steinbach said to Yale Daily News.
One of the drawbacks of nanoparticles as therapeutics is that they can cause inflammation, but according to Steinbach, the use of PLGA, which is FDA-approved and biodegradable, reduces this risk.