Posts Tagged ‘flu viruses’
New Drug Can Treat Almost Any Viral Infection By Killing the Body’s Infected Cells
Viruses work by inserting themselves into a cell and hijacking its machinery for its own use. The invaded cell then creates more copies of the virus, which involves creating long strings of double-stranded RNA — which contains the virus’ genetic material, like DNA contains ours.
When the virus is done copying itself, its hostage cell usually dies, from the virus bursting through its walls (lysis), changes to the cell’s outer membrane, and from apoptosis, or programmed cell death.
Human cells have plenty of defenses against viral invasion, including proteins that attach to the double-stranded RNA, preventing the virus from replicating itself after successful invasion.
This new drug therapy combines those dsRNA proteins with a protein that induces apoptosis. It’s called a DRACO, Double-stranded RNA Activated Caspase Oligomerizer.
When one end of the DRACO binds to dsRNA, it signals the other end of the DRACO to induce cell suicide, an explains. In this way, the cell is killed before the virus can take over and eventually kill it anyway. If there is no dsRNA, the healthy cells are left alone.
“In theory, it should work against all viruses,” said Todd Rider, a senior staff scientist at MIT’s Lincoln Laboratory who invented the new technology.
A handful of drugs can target specific viruses by interfering with their replication process, through addition of modified DNA building blocks or the blocking of enzymes the viruses need to stimulate the replication process. But viruses are wily bugs, and they can evolve to resist these treatments.
The DRACO therapy could be effective because it targets the host cell, not just the virus.
Rider and colleagues are testing DRACO against more viruses in mice, according to MIT. Rider hopes to license the technology for trials in larger animals and for eventual human clinical trials, too.
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Study Turns Up Viral Key That Might Lead to Universal Flu Treatment
The influenza A virus contains eight individual single-stranded RNA segments, each of which has to make protein as well as new segments, in processes called transcription and replication. The multitasking strands must prioritize their work, so they must start with transcription and move on to replication. Researchers at Mount Sinai School of Medicine in New York figured out how to prevent RNA from starting the replication process. Their results were published June 1 online in the Proceedings of the National Academy of Sciences.
Using a novel process called deep sequencing, the team found a small viral RNA segment, or svRNA, that is integral to the change. Inhibiting the svRNA from doing its work stymies replication, and therefore slows the spread of the virus.
Even better, influenza A shares this trait with its viral cousins, influenza B and C, meaning the svRNA switch can be used to stop all kinds of flu -- even the H1N1 flu. As an added bonus, if the virus is prevented from replicating, it stays in transcription mode and produces more proteins. This helps the body's immune system build up its defenses, according to Benjamin tenOever, an assistant microbiology professor at Mount Sinai and a study author.
The process used to make this discovery is also groundbreaking, the researchers say. The deep sequencing allowed the scientists to obtain millions of small RNAs from cells in an unbiased fashion, according to a Mount Sinai release.
The next step is to find a way to introduce RNA "antagonists" to inhibit the svRNA's switch function, tenOever says. That's still a long way off, but the knowledge that RNA can be switched off means that a universal flu treatment is a possibility.
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