Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Potential new herpes therapy studied

05.02.2009
A new therapy being developed at the University of Florida could, in time, produce another weapon for the fight against herpes.

The gene-targeting approach uses a specially designed RNA enzyme to inhibit strains of the herpes simplex virus. The enzyme disables a gene responsible for producing a protein involved in the maturation and release of viral particles in an infected cell.

The technique appears to be effective in experiments with mice and rabbits, but further research is required before it can be attempted in people who are infected with herpes.

"If things worked out the best they could, I think this could be a measure to prevent recurrence, and that would help a lot of people — and even if it just reduced severity, it would give us another therapy in cases where there is drug resistance," said David Bloom, Ph.D., a virologist at the UF College of Medicine who leads the interdisciplinary research team investigating the new therapy.

The work was published in the Journal of Virology in August.

The HSV-1 strain of the herpes virus causes cold sores or fever blisters around the mouth, genital herpes, a deadly but rare type of encephalitis, and keratitis, a scarring of the cornea that leads to vision loss. HSV-2 is the more common cause of genital herpes.

Existing herpes treatments work because the active ingredients target viral building blocks, and become incorporated into the virus' genetic material and shut down its ability to make copies of itself. In so doing, the drugs limit the severity of herpes lesions.

"They work pretty well, and they keep the disease in check, but there's no real cure," said Alfred Lewin, Ph.D., a molecular geneticist on the research team.

Current treatments also can cause inflammation, and in many people the virus becomes resistant and there is no back-up medication. In HSV keratitis, even after a corneal transplant the virus can hide out in nerve cells and cause re-infection.

"Our approach would keep it from popping up again," Lewin said.

The UF team — which also includes researchers and clinicians from obstetrics and gynecology, orthopedics and ophthalmology and the university's Genetics Institute — came up with a way to cut the virus' RNA to prevent reactivation.

By designing special enzymes called hammerhead ribozymes, the researchers were able to target a so-called "late" gene that releases its protein product relatively late after infection. With late genes, partial corruption of the genetic material is sufficient to shut down virus production, as opposed to "early" genes, which would require total inactivation to hinder the process.

"What I think is remarkable with the technology is its versatility — you can design ribozymes that will be effective against any pathogenic virus you're interested in inhibiting," said John M. Burke, a professor of microbiology and molecular genetics at the University of Vermont, who has studied the use of ribozymes for treating viral infections.

Burke, who is not affiliated with the research at UF, said that finding the way to get the ribozyme into an infected cell or animal or person in such a way that it can be active once inside is "the hard part" of these types of experiments.

The University of Florida team packaged the enzyme inside an adenovirus — the type of virus that causes the common cold — and injected it into the mice. Afterward, the animals were infected with potentially lethal doses of the HSV-1 virus. As a control, other mice were injected with green fluorescent protein before being exposed to the virus.

Ninety percent of the mice that were treated with the ribozyme survived, whereas the survival rate was less than 45 percent in mice not given the special enzyme.

Analysis of tissue from treated mice revealed lower viral DNA levels in the feet, nerve cells called dorsal root ganglia and the spinal cord than in mice not treated with the ribozyme.

The approach has also been tested in mouse tissue and in rabbits.

"They have found a very good experimental system in which they can convincingly show significant antiviral activity," Burke said.

But the researchers still need to do more checks to see whether it is safe to move to human testing. Also, they want to develop more than one ribozyme, because having enzymes that attack different places on the viral RNA during replication helps prevent the virus from successfully mutating to resist treatment. They are also trying different ways of delivering the enzyme to the host cells.

One delivery technique for the eye is called iontophoresis, in which a low current pushes the treatment into the cells. The ribozyme could also be formulated into a cream to be used topically on other parts of the body.

"I would like to have it where you put it on once and forget about it," Lewin said.

The work is funded by University of Florida Office of Translational Research, Research to Prevent Blindness and The Burroughs Wellcome Fund.

"I think we've gotten it to the point where it looks promising," Bloom said.

Czerne M. Reid | EurekAlert!
Further information:
http://www.ufl.edu

More articles from Health and Medicine:

nachricht The genes are not to blame
20.07.2018 | Technische Universität München

nachricht Targeting headaches and tumors with nano-submarines
20.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>