A research team at Ajou University School of Medicine has proposed a new mechanism connecting gut bacteria to Parkinson's disease, pointing to a specific E. coli gene and a metabolic byproduct as factors that may influence gene activity in dopamine neurons. The work, led by Lee Eun-jung of the Department of Brain Science and Park Dong-kyu of the Department of Neurology, was reported by 재활뉴스 and other Korean outlets on November 3, 2026.
Parkinson's disease is a degenerative neurological condition in which dopamine-producing neurons in the brain are gradually lost. According to 재활뉴스, growing evidence has tied gut microbes to the disease, but which bacterial genes and substances reach brain neurons has remained unclear.
Why it matters
The study offers a concrete molecular route — from a bacterial gene, through a metabolite, to the expression of a human gene involved in neuron function — rather than a general association between gut flora and Parkinson's. That specificity could give future research a defined target to test. The authors and the reporting both stress that direct causation in people and any therapeutic use remain unproven and require further study.
What the patient samples showed
The team analyzed stool from Parkinson's patients and found that E. coli's hns gene was relatively abundant in the group with "body-first" Parkinson's, a subtype in which pathological changes are thought to begin in the gut and other parts of the body before reaching the brain, according to the reporting.
In a separate analysis of patients' blood, the body-first group had higher concentrations of methylglyoxal (MG) than the brain-first group. MG is produced during metabolic processes in both bacteria and the human body, and can harm cells when it accumulates excessively.
Experiments in worm and mouse models
The researchers then turned to a nematode model of Parkinson's disease. When the worms were fed E. coli from which the hns gene — involved in MG production — had been removed, damage to dopamine neurons decreased, 재활뉴스 reported. Adding MG back eliminated that protective effect, suggesting the gene and the metabolite can influence dopamine neuron damage.
Further analysis identified the worm gene rig-5 as involved in the protective effect, which led the team to LSAMP, a possible human counterpart. LSAMP is linked to neuron function and the connections between neurons. When MG was applied to human neurons, LSAMP expression fell, and brain tissue from Parkinson's patients also showed lower expression of the gene. In mice colonized with hns-deleted E. coli, by contrast, LSAMP expression rose.
What the team says
Lee said the study's significance lies in proposing a new connecting pathway by which a specific gut E. coli gene and a metabolite can affect gene expression in neurons, according to the reporting, and that the team plans follow-up work to clarify the gut-microbe–Parkinson's link in more detail.
Watch for peer-reviewed publication details and independent replication, particularly studies testing whether the hns–MG–LSAMP route holds in people.
