Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UNC researchers discover how hepatitis C virus reprograms human liver cells

19.12.2012
Hepatitis C virus has evolved to invade and hijack the basic machinery of the human liver cell to ensure its survival and spread.

Researchers at the University of North have discovered how hepatitis C binds with and repurposes a basic component of cellular metabolism known as a microRNA to help protect and replicate the virus.


A cultured liver cancer cell infected with Hepatitis C. The virus, stained red, surrounds the blue-stained nucleus and is in the process of being reproduced by virus within the cytoplasm. Photo courtesy of Takahiro Masaki/UNC Lemon Lab

A cultured liver cancer cell infected with Hepatitis C. The virus, stained red, surrounds the blue-stained nucleus and is in the process of being reproduced by virus within the cytoplasm. Photo courtesy of Takahiro Masaki/UNC Lemon Lab

In a paper published online in the Proceedings of the National Academy of Sciences Dec. 17, researchers in the laboratory of Stanley M. Lemon, MD, professor of medicine and microbiology and immunology and member of UNC Lineberger Comprehensive Cancer Center, the Center for Translational Immunology, and the UNC Center for Infectious Disease, outline the critical role the microRNA known as miR-122 plays in the life cycle of the hepatitis C virus.

A chronic blood-borne virus that attacks the liver, hepatitis C infects more than four million in the United States and more than 130 million worldwide. Deaths from the infection surpass those due to HIV/AIDS in the U.S. The virus is currently the leading factor in liver transplantation and a major cause of liver cancer, the third most fatal cancer worldwide and the ninth most deadly in the United States. Chronic hepatitis virus infections factor into more than two-thirds of liver cancer deaths.

“There is no cancer in the United States that is increasing in incidence as fast as liver cancer, and that is because of hepatitis C,” said Dr. Lemon.

One question has been why hepatitis C virus specifically targets the liver. The research of Dr. Lemon and his colleagues points to the interaction between the hepatitis virus and miR-122 as the explanation.

The human genome contains around 1,000 microRNAs, strands of cellular material that play a diverse role in regulating gene expression and cellular metabolism. In a healthy liver cell, the microRNA miR-122 regulates the activity and decay of numerous cellular RNAs responsible for the production of proteins. It normally functions to block protein expression or to promote degradation of RNAs in the cell. The hepatitis C virus genome is entirely RNA, but miR-122 acts on it in a completely different manner - stabilizing it and enhancing its ability to produce viral proteins. In effect, it promotes and protects the invader.

“MicroRNAs almost always promote the degradation of cellular RNAs. This is actually stabilizing the viral RNA,” said Dr. Lemon.

While Dr. Lemon’s team has explored the manner in which hepatitis C exploits miR-122 to protect the viral RNA in previous publications, the new research suggests a much deeper bond between the microRNA and virus. Hepatitis C RNA contains a site that binds directly to the microRNA, and the team has shown that the presence of miR122 is actually crucial for functioning of the virus. Dr. Lemon believes the virus has evolved a unique dependency and that it requires the host’s microRNA to reproduce.

“It is a relationship that is unique to hepatitis C and not seen, as far as we know, with any other virus,” said Dr. Lemon.

Because of the importance of miR-122 to the replication of hepatitis C, the microRNA presents a promising target for new drugs. The pharmaceutical industry has already begun developing therapies that target miR-122. Dr. Lemon said that his research will help explain the underlying biology behind why these drugs work and suggest new possibilities for treatment by targeting other enzymes and proteins that play a role in the interactions between the virus and miR-122.

“If you target miR-122 with a therapeutic that blocks its function or sequesters it so it is no longer accessible to the virus, the replication of the virus is severely impaired,” said Dr. Lemon.

This work was supported by National Institutes of Health Grants R01-AI095690 and P20-CA150343 and the North Carolina University Cancer Research Fund.

William Davis | EurekAlert!
Further information:
http://www.unc.edu

More articles from Life Sciences:

nachricht Learning from Nature: Genomic database standard alleviates search for novel antibiotics
02.09.2015 | Max-Planck-Institut für marine Mikrobiologie

nachricht Orang-utan females prefer cheek-padded males
02.09.2015 | Max Planck Institute for Evolutionary Anthropology, Leipzig

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: How wind sculpted Earth's largest dust deposit

China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from University of Arizona geoscientists. The study is the first to explain how the steep-fronted plateau formed.

China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from...

Im Focus: An engineered surface unsticks sticky water droplets

The leaves of the lotus flower, and other natural surfaces that repel water and dirt, have been the model for many types of engineered liquid-repelling surfaces. As slippery as these surfaces are, however, tiny water droplets still stick to them. Now, Penn State researchers have developed nano/micro-textured, highly slippery surfaces able to outperform these naturally inspired coatings, particularly when the water is a vapor or tiny droplets.

Enhancing the mobility of liquid droplets on rough surfaces could improve condensation heat transfer for power-plant heat exchangers, create more efficient...

Im Focus: Increasingly severe disturbances weaken world's temperate forests

Longer, more severe, and hotter droughts and a myriad of other threats, including diseases and more extensive and severe wildfires, are threatening to transform some of the world's temperate forests, a new study published in Science has found. Without informed management, some forests could convert to shrublands or grasslands within the coming decades.

"While we have been trying to manage for resilience of 20th century conditions, we realize now that we must prepare for transformations and attempt to ease...

Im Focus: OU astrophysicist and collaborators find supermassive black holes in quasar nearest Earth

A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.

The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...

Im Focus: What would a tsunami in the Mediterranean look like?

A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).

Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking conference in Heidelberg for outstanding mathematicians and computer scientists

20.08.2015 | Event News

Scientists meet in Münster for the world’s largest Chitin und Chitosan Conference

20.08.2015 | Event News

Large agribusiness management strategies

19.08.2015 | Event News

 
Latest News

Tiny Drops of Early Universe 'Perfect' Fluid

02.09.2015 | Physics and Astronomy

Learning from Nature: Genomic database standard alleviates search for novel antibiotics

02.09.2015 | Life Sciences

International research project gets high level of funding

02.09.2015 | Awards Funding

VideoLinks
B2B-VideoLinks
More VideoLinks >>>