Are Ancient Viruses The Cause of Modern Neurological Disease?

The deadliest neurological diseases may not be anything new to humanity; as a matter of fact, their mechanisms may be written in our DNA. According to new research from the University of Dusseldorf, viruses insert themselves into our DNA, contributing over time to the framework of various unsolved diseases, like multiple sclerosis. 

The study warns that, actually, that as much as 8 percent of our DNA might have come from viruses.  More specifically, retroviruses become entwined with our DNA because, of course, they have the ability to reverse normal processes of DNA reading to actually write themselves into the genome of the host. 

Now, retroviruses are very old: data shows they started merging with our earliest, primordial human ancestors several million years ago.  Over the course of several millennia, most of our DNA remnants—essentially, human endogenous retroviruses (HERVs)—have been silenced by generations of mutation. Other DNA remnants evolved—over the same period of time—as defense against these rival viruses, and this became the prototypical immune system that now protects us from infection.

At the same time, scientists theorize that HERVs might actually be the causative missing link in many of those previously mentioned “unsolved” neurological diseases. 

Lead study author Professor Patrick Kuery explains human endogenous retroviruses have long been implicated in the onset and progression of many diseases, including multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), and schizophrenia.  In fact, he argues, “Dormant HERVs can be reactivated by environmental factors such as inflammation, mutations, drugs, or infection with other viruses, so could provide a mechanism for their well-established epidemiological link to these disorders.”

Actually, there is a host of evidence that links HERVs to MS.

Kuery goes on to divulge that MS is caused by a direct autoimmune attack on the fatty coating around nerve cells—the myelin sheath—within the brain and spinal cord.  Of course, simply knowing of the link still does not quite explain what sets off the attacks. 

A handful of studies suggest it is the reactivation of these HERVs that could be the trigger. Apparently those who suffer certain diseases have higher levels of HERV RNA and protein in the brain and spinal cord fluid. In fact, the studies suggest HERV proteins could trigger autoimmunity through something called “molecular mimicry.”  This process, essentially, fool the immune system into damaging myelin (in the case of MS) when it tries to attack HERVs.

The results of this study have been published in the journal Frontiers in Genetics.