Hepatitis C virus survives by hijacking liver microRNA: study

January 2, 2012 in Diseases, Conditions, Syndromes

Viral diseases are still one of the biggest challenges to medical science. Thanks to thousands of years of co-evolution with humans, their ability to harness the biology of their human hosts to survive and thrive makes them very difficult to target with medical treatment.

Scientists at the University of North Carolina at Chapel Hill, working with colleagues from the University of Colorado, have shown for the first time how a small RNA molecule that regulates gene expression in human liver cells has been hijacked by the C to ensure its own survival – helping medical scientists understand why a new antiviral drug appears to be effective against the virus.

MicroRNAs are involved in regulating the expression of genes in cells, usually by blocking the production of key proteins or by destabilizing the messenger RNAs that encode the cell's proteins as it grows and divides. Normally they act by downregulating gene expression. The research team found that the binding of a prominent microRNA in liver cells, called miR-122, to the viral RNA results in its stabilization, promoting efficient replication of the virus genome in the liver and supporting the virus' lifecycle.

"The hepatitis C virus has done two very interesting things with miR-122," says Stanley M. Lemon, MD, professor of medicine and microbiology and immunology and a member of UNC Lineberger Comprehensive Cancer Center and the Center for Translational Immunology.

"First, it has evolved a unique relationship with a key regulator, since miR-122 represents about half of all microRNAs present in the liver. Second, the virus has usurped a process that usually downregulates to upregulate the stability of its RNA and expression of viral proteins needed for its lifecycle. It's a classic example of how viruses subvert normally beneficial functions of the cell to their own nefarious purposes."

Work by Dr. Lemon and his colleagues in 2005 helped to demonstrate that miR-122 was required for hepatitis C to replicate itself, but the mechanism was not understood. Now the UNC research team has shown how it works, which helps to explain how a new experimental antiviral drug target the virus. The drug, called an "antagomer", binds to miR-122 and sequesters it in the liver and thus destabilizes the viral genome, accelerating its degradation in the liver. Results of the most recent study are published online this week in the journal Proceedings of the National Academy of Sciences.

is a continuing public health problem, which is difficult to measure because symptoms occur months to years after infection. The Centers for Disease Control and Prevention estimates as many as 4 million people in the United States may be persistently infected with , and most do not know they are infected. More than a third of those who are long-term carriers may develop chronic liver disease or cancer, a deadly form of cancer that is becoming increasingly common due to the spread of this virus.

Journal reference: Proceedings of the National Academy of Sciences search and more info website

Provided by University of North Carolina

4.8 /5 (4 votes)  

Rank 4.8 /5 (4 votes)
Relevant PhysicsForums posts

More news stories

Flesh-Eating bacteria no cause for panic, experts say

(HealthDay) -- Despite scary headlines by the score, most people don't have to fear that they'll be the next victim of the so-called flesh-eating bacteria disease, experts say.

Diseases, Conditions, Syndromes created May 25, 2012 | popularity not rated yet | comments 0

World Health Assembly endorses new plan to increase global access to vaccines

Ministers of Health from 194 countries at the Sixty-fifth World Health Assembly today endorsed a landmark Global Vaccine Action Plan (GVAP), a roadmap to prevent millions of deaths by 2020 through more equitable access to ...

Diseases, Conditions, Syndromes created May 25, 2012 | popularity not rated yet | comments 0

Physicians definitively links irritable bowel syndrome and bacteria in gut

An overgrowth of bacteria in the gut has been definitively linked to Irritable Bowel Syndrome in the results of a new Cedars-Sinai study which used cultures from the small intestine. This is the first study to use this "gold ...

Diseases, Conditions, Syndromes created May 25, 2012 | popularity not rated yet | comments 0 | with audio podcast

Study provides compelling evidence for an effective new treatment for tinnitus

According to new research, a multidisciplinary approach to treating tinnitus that combines cognitive behaviour therapy with sound-based tinnitus retraining therapy is significantly more effective than currently available ...

Diseases, Conditions, Syndromes created May 24, 2012 | popularity not rated yet | comments 0

Infections may be deadly for many dialysis patients

An infection called peritonitis commonly arises in the weeks before many dialysis patients die, according to a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN). The findings sugges ...

Diseases, Conditions, Syndromes created May 24, 2012 | popularity not rated yet | comments 0


Keep food safety in mind this memorial day weekend

(HealthDay) -- Picnics, parades and cookouts are as much a part of Memorial Day weekend as tributes to the United States' war veterans.

Travel to high altitudes tied to Crohn's, colitis flare-ups

(HealthDay) -- People with inflammatory bowel disease, which includes Crohn's disease and colitis, may be at increased risk for flare-ups when they fly or travel to high altitudes for skiing or mountain climbing, ...

Family history of Alzheimer's affects functional connectivity

(HealthDay) -- Cognitively normal individuals with a family history of late-onset Alzheimer's disease (AD) may display lower resting state functional connectivity in the default mode network (DMN) of the brain, ...

Transvaginal mesh op restores pelvic organ prolapse at price

(HealthDay) -- Transvaginal mesh (TVM) procedures are effective for anatomical restoration of pelvic organ prolapse (POP), but patients report a worsening of sexual function following surgery, according to ...

Of mice and mental models: Neuroscientific implications of risk-optimized behavior in the mouse

(Medical Xpress) -- Regardless of an organism’s biological complexity, every encephalized animal continuously makes under-informed behavioral choices that can have serious consequences. Despite its ubiquity, ...

Weight struggles? Blame new neurons in your hypothalamus

New nerve cells formed in a select part of the brain could hold considerable sway over how much you eat and consequently weigh, new animal research by Johns Hopkins scientists suggests in a study published in the May issue ...