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They found an increased abundance of Streptococcus mutans\u2014a well-known oral bacterium that causes dental caries\u2014in the gut microbiome of Parkinson\u2019s patients. Credit: Neuroscience News<\/p>\nSummary: Scientists have uncovered a direct link between oral bacteria and Parkinson\u2019s disease. They found that Streptococcus mutans, best known for causing cavities, can settle in the gut and release metabolites that reach the brain.<\/p>\n
These metabolites trigger neuronal loss, neuroinflammation, and motor impairments resembling Parkinson\u2019s. The findings suggest that targeting the oral\u2013gut microbiome could lead to novel strategies for preventing or treating the disease.<\/p>\n
Key Facts<\/p>\n
Oral\u2013Gut\u2013Brain Link: Streptococcus mutans can migrate from mouth to gut and affect the brain.Toxic Metabolite: Its metabolite ImP damages dopaminergic neurons and promotes Parkinson\u2019s pathology.Therapeutic Potential: Blocking mTORC1 signaling reduced neuroinflammation and motor symptoms in mice.<\/p>\n
Source: POSTECH<\/p>\n
There is now one more reason to brush your teeth thoroughly every day. Korean researchers have uncovered compelling evidence that oral bacteria, once colonized in the gut, can affect neurons in the brain and potentially trigger Parkinson\u2019s disease.<\/p>\n
The joint research team, led by Professor Ara Koh and doctoral candidate Hyunji Park of POSTECH\u2019s Department of Life Sciences, together with Professor Yunjong Lee and doctoral candidate Jiwon Cheon of Sungkyunkwan University School of Medicine, collaborated with Professor Han-Joon Kim of Seoul National University College of Medicine.<\/p>\n
They found an increased abundance of Streptococcus mutans\u2014a well-known oral bacterium that causes dental caries\u2014in the gut microbiome of Parkinson\u2019s patients. Credit: Neuroscience News<\/p>\n
They have identified the mechanism by which metabolites produced by oral bacteria in the gut may trigger the development of Parkinson\u2019s disease.<\/p>\n
The findings were published online on September 5 in\u00a0Nature Communications.<\/p>\n
Parkinson\u2019s disease is a major neurological disorder characterized by tremors, stiffness, and slowed movement. It affects approximately 1-2% of the global population over the age of 65, making it one of the most common age-related brain diseases.<\/p>\n
Although previous studies suggested that the gut microbiota of individuals with Parkinson\u2019s differs from that of healthy individuals, the specific microbes and metabolites have remained unclear.<\/p>\n
They found an increased abundance of\u00a0Streptococcus mutans\u2014a well-known oral bacterium that causes dental caries\u2014in the gut microbiome of Parkinson\u2019s patients.<\/p>\n
More importantly,\u00a0S. mutans\u00a0produces the enzyme urocanate reductase (UrdA) and its metabolite imidazole propionate (ImP), both of which were present at elevated levels in the gut and blood of patients. ImP appeared capable of entering systemic circulation, reaching the brain, and contributing to the loss of dopaminergic neurons.<\/p>\n
Using mouse models, the researchers introduced\u00a0S. mutans\u00a0into the gut or engineered\u00a0E. coli\u00a0to express UrdA. As a result, the mice showed elevated ImP levels in blood and brain tissue, along with the hallmark features of Parkinson\u2019s symptoms: loss of dopaminergic neurons, heightened neuroinflammation, impaired motor function, and increased aggregation of alpha-synuclein, a protein central to disease progression.<\/p>\n
Further experiments demonstrated that these effects depend on the activation of the signaling protein complex mTORC1. Treating mice with an mTORC1 inhibitor significantly reduced neuroinflammation, neuronal loss, and alpha-synuclein aggregation, and motor dysfunction.<\/p>\n
This suggests that targeting the oral\u2013gut microbiome and its metabolites may offer new therapeutic strategies for Parkinson\u2019s disease.<\/p>\n
\u201cOur study provides a mechanistic understanding of how oral microbes in the gut can influence the brain and contribute to the development of Parkinson\u2019s disease,\u201d said Professor Ara Koh.<\/p>\n
\u201cIt highlights the potential of targeting the gut microbiota as a therapeutic strategy, offering a new direction for Parkinson\u2019s treatment.\u201d<\/p>\n
Funding: The research was supported by the Samsung Research Funding & Incubation Center of Samsung Electronics, the Mid-Career Researcher Program of the Ministry of Science and ICT, the Microbiome Core Research Support Center, and the Biomedical Technology Development Program.<\/p>\n
About this Parkinsons\u2019s disease research news<\/p>\n
Author: Yung-Eui Kang<\/a>
Source: POSTECH<\/a>
Contact: Yung-Eui Kang \u2013 POSTECH
Image: The image is credited to Neuroscience News<\/p>\n