Scientists Use RNAi To Develop Herpes Prevention Cream
Harvard researchers have reported a breakthrough topical treatment that could be used to prevent herpes infection for as long as a week.
Using RNA interference (RNAi), Judy Lieberman, professor of pediatrics at Harvard Medical School, and colleagues have discovered a treatment that works to disable genes necessary to transmit herpes simplex 2 ““ the most common type of herpes, in mice.
“People have been trying to make a topical agent that can prevent transmission, a microbicide, for many years," said Lieberman, a senior investigator at the Immune Disease Institute whose findings are published in the journal Cell Host and Microbe.
"But one of the main obstacles for this is compliance. One of the attractive features of the compound we developed is that it creates in the tissue a state that’s resistant to infection, even if applied up to a week before sexual exposure. This aspect has a real practicality to it. If we can reproduce these results in people, this could have a powerful impact on preventing transmission."
Massachusetts-based Alnylam Pharmaceuticals Inc is developing the cream, which targets the gene called nectin-1.
But the cream "silencing" nectin-1 took a day or so to become effective. Attacking a second gene called UL29, found in the virus itself, provided immediate protection, they wrote.
"As far as we could tell, the treatment caused no adverse effects, such as inflammation or any kind of autoimmune response," said Lieberman. "And while knocking out a host gene can certainly be risky, we didn’t see any indication that temporarily disabling Nectin-1 interfered with normal cellular function."
"A vaginal microbicide able to protect against HSV-2 transmission could contribute significantly to controlling sexually transmitted diseases," Deborah Palliser of Harvard Medical School in Boston and Albert Einstein College of Medicine in New York and colleagues wrote in the journal Cell Host & Microbe.
The field of RNAi has been hailed as a breakthrough. Awarded the Nobel Prize in 2006, RNAi is a natural cellular process that occurs in all cells of all multicellular organisms that can be manipulated by researchers to switch off specific genes.
The World Health Organization estimates that approximately 536 million people worldwide are infected with herpes simplex virus type 2. It is estimated that one in five Americans have genital herpes, according to the US Centers for Disease Control and Prevention.
The disease poses risks to mothers and children alike as it can be transmitted during birth, making infants more susceptible to risks of brain damage or death.
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