The accidental attack
Friendly fire may be at the root of Parkinson-like diseases
By John Pastor
Scientists have suspected exposure to viruses and other environmental factors may trigger symptoms associated with Parkinson-like diseases, but why such exposure would actually destroy certain areas of the brain has been mysterious.
New research suggests a pathway located at the base of the brain that is essential for the execution of smooth, coordinated movements may be selectively damaged by the friendly fire of the body’s immune response, according to UF and Mayo Clinic Florida scientists writing in Nature Neuroscience.
“In the movie ‘Awakenings,’ it was suggested that people who previously suffered from an infection like the flu developed Parkinsonism, probably because of degeneration in a brain pathway known as the nigrostriatal tract. But the links between infection and subsequent Parkinsonism have always been controversial,” said Todd Golde, M.D., Ph.D., director of the UF College of Medicine’s Center for Translational Research in Neurodegenerative Disease. “Our data show that when a certain master protein that stimulates the immune system and antiviral response is expressed at high levels, it causes neuronal loss primarily in the nigrostriatal tract, thereby creating vulnerability to Parkinson’s and similar movement disorders.”
Known as interferon gamma, the master protein regulates the activity of genes important to the human immune system, and coordinates the body’s defenses against many types of infection. In their study, high levels of interferon gamma resulted in widespread brain inflammation in model systems. Yet, most of the brain did not degenerate — only the nigrostriatal tract.
The discovery gives scientists a target to explore as they search for preventions and treatments for Parkinsonisms, and clues to why different regions of the brain appear to be more vulnerable to neurodegenerative diseases.