Can “good” gut bacteria protect against neurodegenerative diseases?

That’s what researchers at UF/IFAS want to know.

The study, published in iScience on Tuesday, suggests that specific “good” gut bacteria could contribute to preventing these diseases, said Daniel Czyz, assistant professor in the UF/IFAS department of microbiology and cell science. He conducted the study along with Alyssa Walker, a UF/IFAS postdoctoral scholar, and a team of undergraduate students.

One of the key takeaways from the study is that specific bacteria from the gut microbiome affected the proteins associated with neurodegenerative diseases. The team looked at 229 strains of bacteria to see how they affected these proteins.

The team also demonstrated that when the good bacteria colonized in combination with the “bad” bacteria – or bacteria that are suspected of contributing to neurodegenerative diseases – the beneficial microbes canceled out the “bad” ones, he said.

“Targeting the gut has the potential for a therapeutic approach to these diseases,” he said. “The prevalence of Alzheimer’s disease or Parkinson’s disease will double or triple in the next 30 years.”

The bacteria either caused proteins to fold or cluster, known as toxic protein aggregation, or they helped the protein maintain its original shape. The team classified the bacteria into two groups, those that prevented or those that increased toxic protein aggregation, Czyz said.

The gut of patients with neurodegenerative disease lacks the protective bacteria but is rampant with “bad” bacteria that cause protein misfolding, suggesting that changing a patient’s gut microbiome could be a potential strategy for preventing or treating these diseases, he said.

The researchers found that one bacterium, the Prevotella species, provided strong protection against toxic protein aggregation.

The bacteria had a broad effect on stabilizing multiple types of proteins associated with neurodegeneration, he said.

“We found that these good bacteria can actually mount a protective stress response that prevents protein misfolding and toxic aggregation associated with these diseases,” Czyz said. “For decades, scientists have been looking for anything that would activate a protective stress response. These bacteria might give us a clue.”

The big-picture hope is for “good” gut bacteria to be a way to prevent these diseases altogether, but there is still much more work to be done before this strategy can be tested in humans.

Czyz said there’s no treatment or cure for neurodegenerative diseases. If we only knew which bacteria are protective, their introduction into a gut microbiome could affect neurodegenerative diseases, “and now we know which bacteria,” Czyz said.

“At this point, it is unquestionable that microbes contribute to these devastating diseases, but we still don’t understand how,” Czyz added. “Our study reveals important new insights into the role microbes play in neurodegenerative diseases, and it could open new avenues for developing microbial-based therapies in the future.”