Gut microbial production of imidazole propionate drives Parkinson's pathologies

Area of Science:

• Neuroscience
• Microbiology
• Gastroenterology

Background:

• Parkinson's disease (PD) involves dopaminergic neuron loss and alpha-synuclein aggregation.
• The gut microbiome's role in PD is emerging, with microbial metabolites as potential mediators.
• Specific gut microbes and metabolites driving PD neurodegeneration remain unidentified.

Purpose of the Study:

• Identify specific gut microbes and metabolites linked to Parkinson's disease.
• Investigate if gut-derived metabolites can induce neurodegeneration in the brain.
• Elucidate the mechanism by which microbial metabolites contribute to PD pathology.

Main Methods:

• Analyzed gut microbiome and plasma imidazole propionate (ImP) in PD patients.
• Colonized mice with Streptococcus mutans or engineered E. coli expressing UrdA.
• Administered ImP to mice and assessed PD-like symptoms and pathology.
• Investigated the role of mTORC1 signaling in the observed pathology.

Main Results:

• Elevated S. mutans, UrdA, and ImP found in PD patients.
• S. mutans colonization increased systemic and brain ImP, inducing PD-like symptoms in mice.
• ImP administration alone replicated key PD features, including neurodegeneration and motor deficits.
• S. mutans exacerbated alpha-synuclein pathology; mTORC1 activation was crucial.

Conclusions:

• Identified the UrdA-ImP axis in S. mutans as a microbial driver of PD.
• Demonstrated that microbial ImP directly mediates gut-brain axis pathology in PD.
• Established ImP as a key metabolite contributing to dopaminergic neurodegeneration in Parkinson's disease.