# Multi‐omics identifies microbiota‐derived deoxycholic acid as a key mediator of blood‐brain barrier dysfunction in Parkinson's disease

## TL;DR

This study shows that gut bacteria in Parkinson's patients produce bile acids that damage the brain's protective barrier, leading to disease progression.

## Contribution

The study identifies microbiota-derived deoxycholic acid as a novel mediator of blood-brain barrier dysfunction in Parkinson's disease.

## Key findings

- Gut microbiota from Parkinson's patients enriches Bacteroides fragilis and Phocaeicola vulgatus.
- Increased bile acids like deoxycholic acid cause endothelial and pericyte damage in the brain.
- These changes lead to neurodegeneration and motor deficits in germ-free mice.

## Abstract

The gut microbiota derived from Parkinson's disease patients, enriched in Bacteroides fragilis (B. fragilis) and Phocaeicola vulgatus (P. vulgatus), may promote the elevations of deoxycholic acid, iso‐deoxycholic acid, and ursodeoxycholic acid levels in the systemic circulation. The increased serum bile acids, in turn, contribute to the endothelial cell death and pericyte injury possibly through activating interferon alpha response and TGF‐β signaling pathways at the blood‐brain barrier in the midbrain, ultimately leading to the neurodegeneration and motor deficits in the germ‐free mice.