New method of turning off viruses may help control HIV infection, says Jefferson scientist

July 02, 2002

A natural method of disarming some types of viruses may enable scientists to someday treat infections with HIV, the AIDS virus, according to a virologist at Jefferson Medical College.

Taking the lead from the common fruit fly, yeast and worms, scientists have recently shown that it may be possible to use small pieces of genetic material called short interfering RNAs (siRNAs) to inhibit HIV from making more copies of itself.

The process, called RNA interference (RNAi), was first discovered in 1998. It is so novel, says virologist Roger J. Pomerantz, M.D., professor of medicine, biochemistry and molecular pharmacology and chief of the division of infectious diseases at Jefferson Medical College of Thomas Jefferson University in Philadelphia, that scientists only now are beginning to understand its potential to treat disease. "What's so exciting for HIV therapy is that it may be a potent way of specifically inhibiting the virus," says Dr. Pomerantz, whose commentary accompanies a paper on the topic in the July 2002 issue of Nature Medicine.

"Does it [RNAi] work in mammals? That would be the Holy Grail," says Dr. Pomerantz, who is also director of the Center for Human Virology at Jefferson Medical College. "Researchers are showing it in mouse cells and now a team has demonstrated it in human cells."

So-called "gene silencing" isn't new. According to Dr. Pomerantz, scientists have known for several decades that organisms can and do shut off the expression of certain genes. But, he says, no one until recently has been able to show this was occurring during the gene replication process. Scientists showed that they could stop a gene from replicating by degrading the gene's RNA and making its protein product.

Researchers learned several years ago that certain organisms - some worms, fruit flies, yeast and even plants - use a type of RNA called double-stranded RNA (dsRNA) to shut off genes. Dr. Pomerantz explains that dsRNA is cut up by an enzyme, "Dicer," into smaller siRNAs, which in turn attach to RNA being made by the cell, rendering it useless.

Scientists showed recently that RNAi could work in mammalian cells. In the current issue of Nature Medicine, researchers at Massachusetts Institute of Technology reported a series of experiments demonstrating how siRNAs might be used to fight HIV, which is an RNA virus. They used siRNAs in two ways. They showed they could silence both cellular genes necessary for HIV infection and also use siRNAs to quiet an HIV gene itself.

Dr. Pomerantz points out that the MIT report is an important step in understanding the process. "This [MIT work] is a proof of concept," he says. "The MIT team showed RNAi could work for HIV.

"Now, we need to figure out how it works and how long it lasts," he says. "Does it spread between cells? How robust is it in inhibiting HIV? Can we use it against virtually any RNA virus?" RNAi may also be useful against cancer-causing oncogenes, he adds.

"I think it [this technology] is going to explode," Dr. Pomerantz says. "It has the potential to lead to novel forms of drugs for many diseases, but there's a lot of science to be done first to catch up to these observations."
-end-
Contact: Steve Benowitz or Phyllis Fisher, 215-955-6300. After Hours: 215-955-6060

Thomas Jefferson University

Related HIV Articles from Brightsurf:

BEAT-HIV Delaney collaboratory issues recommendations measuring persistent HIV reservoirs
Spearheaded by Wistar scientists, top worldwide HIV researchers from the BEAT-HIV Martin Delaney Collaboratory to Cure HIV-1 Infection by Combination Immunotherapy (BEAT-HIV Collaboratory) compiled the first comprehensive set of recommendations on how to best measure the size of persistent HIV reservoirs during cure-directed clinical studies.

The Lancet HIV: Study suggests a second patient has been cured of HIV
A study of the second HIV patient to undergo successful stem cell transplantation from donors with a HIV-resistant gene, finds that there was no active viral infection in the patient's blood 30 months after they stopped anti-retroviral therapy, according to a case report published in The Lancet HIV journal and presented at CROI (Conference on Retroviruses and Opportunistic Infections).

Children with HIV score below HIV-negative peers in cognitive, motor function tests
Children who acquired HIV in utero or during birth or breastfeeding did not perform as well as their peers who do not have HIV on tests measuring cognitive ability, motor function and attention, according to a report published online today in Clinical Infectious Diseases.

Efforts to end the HIV epidemic must not ignore people already living with HIV
Efforts to prevent new HIV transmissions in the US must be accompanied by addressing HIV-associated comorbidities to improve the health of people already living with HIV, NIH experts assert in the third of a series of JAMA commentaries.

The Lancet HIV: Severe anti-LGBT legislations associated with lower testing and awareness of HIV in African countries
This first systematic review to investigate HIV testing, treatment and viral suppression in men who have sex with men in Africa finds that among the most recent studies (conducted after 2011) only half of men have been tested for HIV in the past 12 months.

The Lancet HIV: Tenfold increase in number of adolescents on HIV treatment in South Africa since 2010, but many still untreated
A new study of more than 700,000 one to 19-year olds being treated for HIV infection suggests a ten-fold increase in the number of adolescents aged 15 to 19 receiving HIV treatment in South Africa, according to results published in The Lancet HIV journal.

Starting HIV treatment in ERs may be key to ending HIV spread worldwide
In a follow-up study conducted in South Africa, Johns Hopkins Medicine researchers say they have evidence that hospital emergency departments (EDs) worldwide may be key strategic settings for curbing the spread of HIV infections in hard-to-reach populations if the EDs jump-start treatment and case management as well as diagnosis of the disease.

NIH HIV experts prioritize research to achieve sustained ART-free HIV remission
Achieving sustained remission of HIV without life-long antiretroviral therapy (ART) is a top HIV research priority, according to a new commentary in JAMA by experts at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

The Lancet HIV: PrEP implementation is associated with a rapid decline in new HIV infections
Study from Australia is the first to evaluate a population-level roll-out of pre-exposure prophylaxis (PrEP) in men who have sex with men.

Researchers date 'hibernating' HIV strains, advancing BC's leadership in HIV cure research
Researchers have developed a novel way for dating 'hibernating' HIV strains, in an advancement for HIV cure research.

Read More: HIV News and HIV Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.