The Periodontal Pathogen Fusobacterium nucleatum Exacerbates Alzheimer's Pathogenesis via Specific Pathways

Area of Science:

• Neuroscience
• Microbiology
• Oral Health

Background:

• Alzheimer's Disease (AD) is a leading cause of dementia with significant societal impact.
• Periodontitis, an oral inflammatory disease, has been increasingly linked to AD.
• Fusobacterium nucleatum, a key pathogen in periodontitis, has been detected in AD patients, but a causal link remains unclear.

Purpose of the Study:

• To investigate the causal relationship and underlying mechanisms between Fusobacterium nucleatum infection and Alzheimer's Disease pathogenesis.
• To determine if F. nucleatum can activate microglial cells and exacerbate AD symptoms in a mouse model.

Main Methods:

• In vitro experiments assessed F. nucleatum's effect on microglial cell activation, proliferation, and inflammatory marker expression (TNF-α, IL-1β).
• In vivo studies utilized 5XFAD mice with induced periodontitis to evaluate cognitive impairment, beta-amyloid deposition, and Tau phosphorylation.
• Proteomic data is available via ProteomeXchange (identifier PXD033147).

Main Results:

• F. nucleatum significantly activated microglial cells, causing morphological changes and increased TNF-α and IL-1β expression.
• Infected mice exhibited worsened cognitive deficits, elevated beta-amyloid accumulation, and increased Tau phosphorylation in the brain.
• These findings demonstrate a direct link between F. nucleatum infection and exacerbated AD pathology.

Conclusions:

• Fusobacterium nucleatum may act as a risk factor contributing to the pathogenesis of Alzheimer's Disease.
• The study provides evidence for a potential mechanism linking periodontal disease to neurodegeneration.
• Further research is ongoing to elucidate the specific molecular pathways involved.