Gut Macrophages Linked To Parkinson’s Transmission To Brain, Study Finds
Researchers at University College London (UCL), working with collaborators from several European research institutions and the University of Pennsylvania, have identified a crucial role for gut immune cells in the early stages of Parkinson’s disease (PD), providing new insight into how the condition may originate in the gut and spread to the brain.
The study, published in Nature, highlights potential targets for early diagnosis and intervention.
Parkinson’s disease is a progressive neurodegenerative disorder marked by the accumulation of misfolded alpha-synuclein (αS) proteins and the loss of dopamine-producing neurons. Motor symptoms, such as tremors and rigidity, typically appear only after substantial neuronal damage has occurred. Prior to these symptoms, many patients experience gastrointestinal dysfunction, particularly constipation, suggesting early involvement of the enteric nervous system (ENS), the network of nerves controlling the digestive tract.
The study demonstrates that muscularis macrophages (ME‑Macs), specialized immune cells residing in the intestinal wall, play a key role in capturing misfolded αS and modulating immune responses that propagate pathology toward the brain. Using mouse models of PD, the researchers observed that ME‑Macs contained aggregated αS and influenced the expansion of T cells, which migrate from the gut to the central nervous system during disease progression.
Experimental depletion of ME‑Macs reduced αS accumulation in both the ENS and the brain, decreased T cell migration, and lessened neurodegeneration and motor dysfunction in animal models. These findings indicate that gut macrophages are active contributors to disease progression, rather than passive bystanders. Additionally, blocking T cell trafficking from the gut to the brain mitigated PD-like neurodegeneration, underlining the importance of immune cell migration in the development of Parkinson’s pathology.
The research involved a combination of immunology, neurology, and molecular biology techniques, with major contributions from the UK Dementia Research Institute at UCL, the UCL Queen Square Institute of Neurology, and affiliated centres in the United States. This international collaboration provides one of the first mechanistic explanations for how early immune changes in the gut can trigger a cascade of events leading to central nervous system involvement in Parkinson’s disease.
While further studies are required to validate these findings in humans, the study suggests that gut macrophages and their interactions with other immune cells could serve as early biomarkers and potential therapeutic targets.
By focusing on immune processes in the gut before neurological symptoms appear, researchers hope to enable earlier, precision-based interventions, potentially improving long-term outcomes for Parkinson’s patients.
