My PD Story

Searching for Gut Bacteria That May Lead to Parkinson’s Disease 

Research has shown that the trillions of bacteria that live in our gut have incredible influence over our health — offering protection from many illnesses and diseases. Recent studies suggest that alterations in gut bacteria may drive the development or progression of  Parkinson’s disease (PD).  

Gut bacteria have been linked to PD development in different ways, like driving the accumulation of misfolded proteins or even inhibiting the effectiveness of PD medication. However, identifying the specific types, or strains, of bacteria most linked to PD and understanding what attributes they possess to propel the disease has been a daunting challenge for scientists.  

Chris Smillie, PhD, the recipient of a Parkinson’s Foundation Impact Award, is using cutting-edge genetic tools and techniques to comb through trillions of bacterial cells to find the ones most associated with PD. Through his research, he aims to identify how their activity and function may contribute to the disease, and how we might be able to target gut bacteria to slow, stop or prevent PD progression. 

Gut bacteria are highly adaptable microbes, capable of rapid evolution in response to changes in their environment. “Health-adapted” bacteria strains, which thrive in a healthy gut, might offer a protective benefit for the person they live in by fighting off viruses or other invaders. Conversely, “illness-adapted” strains may thrive in environments of gastrointestinal distress, potentially evolving to cause and maintain such distress.  

Following the growing evidence pointing toward gut bacteria affecting PD, Dr. Smillie believes that there are “PD-adapted” bacteria strains that adapt to and consequently cause conditions that progress PD. 

To figure out which bacteria might be PD-adapted, Dr. Smillie and his research team at the Massachusetts General Hospital in Boston, MA, a Parkinson’s Foundation Center of Excellence, will utilize stool samples from nearly 3,000 study participants: some with PD, some without PD as controls, and others with inflammatory bowel diseases (to isolate PD-adaptation from other gut-distressing adaptations).  

After analyzing all the bacterial DNA from these samples, he will use computational tools to find the different strains present as well as map which unique strains are most associated with PD.  

Going further, Dr. Smillie plans to untangle the PD-adapted strains’ evolutionary paths, discovering which genetic changes they underwent over time to become associated with PD. Identifying these changes will also help him understand the functional connections between the strains and PD, uncovering mutations in bacterial proteins that may contribute to disease progression. 

After amassing this staggering amount of genetic data about PD-adapted bacteria, Dr. Smillie hopes his research will provide scientists and doctors with new ways to diagnose and treat PD earlier, by looking at the gut instead of the brain.  

On receiving this award and the impact of his proposed research, Dr. Smillie said “The Parkinson's Foundation Impact Award is an immense honor. With this award my lab will apply powerful computational tools to identify the bacteria that are associated with Parkinson's, which will yield new insights into disease mechanisms, and may guide the development of microbiome-based therapeutics to treat the disease or its gut symptoms.” 

Meet more Parkinson’s researchers! Explore our My PD Stories featuring PD researchers.