Dissecting mechanisms of gut-brain communication in Parkinson’s Disease

People with Parkinson’s Disease (PD) have different types of bacteria in their guts compared to people without neurological diseases. However, we don't know if and how these differences in gut bacteria might cause PD. One idea is that changes in the gut bacteria cause inflammation in the gut, which then spreads to the rest of the body and the brain. Usually, protective “body barriers” prevent harmful substances from traveling from the gut-to-blood (gut-blood barrier), or blood-to-brain (blood-brain barrier). We propose that PD-related bacteria might make these barriers leaky. We will study this by figuring out which gut bacteria are only or mostly in people with PD by (1) collecting and studying stool and blood samples from research participants with and without PD. We will then (2) test whether substances produced by the gut bacteria in PD participants can make the body barriers leakier. A more leaky barrier will allow substances from the gut to leak into the blood and then into the brain. When we successfully complete this project, we will have a better understanding of how gut bacteria contribute to inflammation in the body and in the brain of people with PD.