Microbial metabolites as risk factors for Parkinson’s disease

Researchers at the University of Vienna have discovered a microbial metabolite that destroys dopamine-producing neurons.

From the press release:

“…the researchers focused on a metabolite produced by the bacterium Streptomyces venezuelae. The team isolated and identified this metabolite and exposed it to human dopamine-producing neurons.

The results were clear: The metabolite had a destructive effect that led to neuronal loss similar to Parkinson’s disease.”

Some excerpts from their paper provide some background on other potential factors involved in Parkinson’s Disease:

“The increasing number of idiopathic Parkinson’s disease (PD) cases suggests that environmental factors exist that specifically affect dopaminergic (DAergic) neuron viability. Indeed, several industrial chemicals and pesticides have been implicated to contribute to PD pathogenesis… Metabolites synthesized by bacteria and fungi are also candidates for initiation and perpetuation of the disease.”

“Metabolites produced by the microbiome have been considered relevant factors, as they may affect large populations. Indeed, the gut microbiome of PD patients is different from healthy individuals, and the gut microbiome-brain axis has been shown to be altered in PD. Moreover, neurodegenerative changes of the enteric nervous system occur during early stages of PD pathology. They may predate the onset of motor symptoms by years…. In experimental animals, a link between gut microbiota and PD pathology has been established, as gut stool transferred from PD patients promoted motor dysfunction in mice.

From their paper:

“The toxin production of S. venezuelae may be of limited relevance for most PD cases, as these bacteria typically live in soil. However, elucidation of the neurotoxicant structure can help in identifying the genes involved in its synthesis. Biosynthetic clusters for secondary metabolites often use simple primary metabolites (e.g., amino acids) to build complex new molecules, and the genes for this process can be transmitted horizontally across many bacterial species. Thus, secondary metabolites identified in soil bacteria may also be found in microbes closely associated with human physiology or pathology” 

It’s worth noting soil-based probiotics are available commercially for human use, and I found at least one which claims to contain Streptomyces venezuelae.