Scientists Find Genes in Mice That May Lead to Future Ebola Treatments

As anyone who watches movies like Contagion knows, there are usually a few people who happen to have the right genetics to resist certain virus-causing diseases. Turns out that stories like these are based on fact.

For example, some people reacted less strongly to or were even immune to diseases like the Spanish flu or HIV. And the same may be true for Ebola as well.

Ebola has been ravaging Western Africa for most of 2014 with the numbers of people dying going up day by day. But not everyone who is infected dies. In fact, many people have much less severe symptoms suggesting that perhaps their personal genetics might make them less susceptible to the disease.

Working in a high tech, Ebola-safe lab in Montana, a group of scientists have found that some mice deal better with an Ebola infection than do others.  These researchers looked at 47 genetically distinct lines of mice and found a range of responses from shrugging off the infection to dying horribly. The only differences between these lines were their genetics.

This is the first time scientists have been able to recapitulate an Ebola infection in mice. At the very least, the susceptible mice from this study may one day serve as a model system for studying new Ebola treatments. And if human and mouse genetics are similar enough, the resistant ones just might lead us to new treatments as has happened with HIV and AIDS.

Early in the AIDS epidemic, scientists noted that certain people (mostly sex workers in places like Nairobi) appeared to be immune to HIV. A close look at the immune people’s genomes showed they shared a certain version of the CCR5 gene, CCR5 delta 32. Not only did this teach scientists a lot about how our immune systems work, but it has also led to some promising new treatments.

By identifying the CCR5 gene, scientists had found a new way to attack HIV and treat AIDS. If the mouse work translates to human resistance (definitely a big IF), then two genes, Tie1 and Tek, could show real promise as new avenues for treating the bleeding associated with Ebola. And a deeper look at the genes of the resistant mice may find other genes that could lead to new treatments for other symptoms as well.

Keeping the Bleeding at Bay

One of the most disturbing features of Ebola is the bleeding it causes out of various parts of the body including the eyes and the nose. But again, not everyone with Ebola suffers from this “hemorrhagic syndrome.” This is also true of the mice in these studies.

When the researchers in this study compared the effect Ebola was having on the genes of the resistant and susceptible mice, two genes, Tie1 and Tek, stood out as being interesting because both were turned on to higher levels in the resistant mice. Since both genes are involved in repairing broken arteries, veins and capillaries, their increased expression might help explain why there was so much less bleeding in the resistant mice.

Basically these mice had a better system for fixing leaky blood vessels which helped staunch the bleeding. Turning to the DNA, the researchers couldn’t find any obvious reason the tie1 gene was turned up in resistant mice. But it was a different story for Tek. Most of the resistant lines shared a common version of Tek that might explain its increased expression.

Whatever the reason, these and experiments like these might be able to point scientists towards new treatments for Ebola. Perhaps goosing these or related genes in infected people might hold off the bleeding long enough for their bodies to mount a successful attack against the virus. Or maybe it was a mouse-specific effect and these two genes will not turn out to be helpful.

Still, this work gives scientists new pathways to study that may eventually lead to better treatments for Ebola. This research may not help with this outbreak, but it could have a real impact on the next big one.