The US team showed that treatment with antibiotics was able to reduce movement symptoms and the build-up of clumps of alpha-synuclein in mice with a gene that causes the condition.
The findings could lead to new treatments that can slow, stop or even prevent the development of the condition.
What the team did
Researchers based at the California Institute of Technology studied mice with a small genetic change that causes them to produce too much of the protein alpha-synuclein.
As the mice age, they naturally develop clumps of alpha-synuclein inside brain areas involved in controlling movement, and mobility problems similar to those experienced by people with Parkinson's.
The researchers raised the mice in either normal conditions or in a germ-free environment. Remarkably, mice raised in the germ-free cages had almost normal mobility and much reduced build-up of protein clumps in their brains.
Treating mice raised in normal conditions with antibiotics had a similar protective effect.
Crucially, when mice raised in the germ-free cages were treated with chemicals released by gut microbes or gut microbes from people with Parkinson's their movement problems worsened.
Developing new treatments
Dr Arthur Roach, Director of Research at Parkinson's UK, says:
"In recent years, evidence has been growing that Parkinson's may begin in the gut, but the chain of events involved has so far remained a mystery.
"This paper shows for the first time a way in which one of the key players in Parkinson's, the protein alpha-synuclein, may have its actions in the brain modified by gut bacteria.
"The greatest need in Parkinson's research is to develop treatments that can stop or slow down the processes that first lead to the condition, something no current treatments can do.
This study provides a fresh insight into how Parkinson's develops
"This work opens an exciting new avenue of study on the gut-brain connection in Parkinson's. There are still many questions to answer but we hope this will trigger more research that will ultimately revolutionise treatment options for Parkinson's."
What are the next steps?
This study provides a fresh insight into how Parkinson's develops and exciting new opportunities to develop treatments that can intervene.
Current antibiotics are not a viable option as we know that long-term, high-strength antibiotic use comes with significant health risks.
Up to a trillion microbes live in our gut. Many are beneficial so the next step is to pinpoint those that are harmful so that treatments can be developed to target the damaging ones while leaving the beneficial ones unharmed.
It takes many years to turn a scientific discovery like this one into a new treatment that can be tested in people. That's why we are investing in taking the best research ideas forwards faster through our virtual biotech.
Did you know...
70% of all neurons in our bodies, outside the brain stem, are in our intestines?
Find out more about the potential of gut bacteria in new treatments for Parkinson's.